1. Field of the Invention
The present invention relates to a rear height controller for a vehicle, particularly to a rear height controller which is effective in keeping good control and stability of the vehicle against a single shock caused by a sporadic bump or dip of a road surface on which the vehicle is running.
2. Prior Art
Height controllers which alter a vehicle body height when the acceleration of the vertical movement of the wheels or the body detected by a body height sensor exceeds a certain level and sustains the level for more than a preset time interval, are proposed in, for example, the published unexamined Japanese patent applications Nos. 57-172808, 59-23713 and 59-23712. They are proposed in order to improve the ride comfort of the vehicle when the vehicle is running on a rough road.
However, under the above-mentioned conventional control, the vehicle is not judged to be running on a rough road until large irregularities are consecutively detected by the vehicle height sensor. When the vehicle is running on a flat road and a sporadic bump or dip of the road surface is detected by the vehicle height sensor, the conventional controllers have no effect, since the road surface having such sporadic irregularities is not judged to be a rough road by the controllers. Therefore, rolling of the vehicle is not prevented and the ride comfort is not improved by the conventional vehicle height controllers when the road surface has sporadic bumps or dips.